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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "bootcontrolhal"
#include "GptUtils.h"
#include <android-base/file.h>
#include <errno.h>
#include <linux/fs.h>
#include <log/log.h>
#include <zlib.h>
namespace aidl::android::hardware::boot {
namespace {
static int ValidateGptHeader(gpt_header *gpt) {
if (gpt->signature != GPT_SIGNATURE) {
ALOGE("invalid gpt signature 0x%lx\n", gpt->signature);
return -1;
}
if (gpt->header_size != sizeof(gpt_header)) {
ALOGE("invalid gpt header size %u\n", gpt->header_size);
return -1;
}
if (gpt->entry_size != sizeof(gpt_entry)) {
ALOGE("invalid gpt entry size %u\n", gpt->entry_size);
return -1;
}
return 0;
}
} // namespace
GptUtils::GptUtils(const std::string dev_path) : dev_path(dev_path), fd(0) {}
int GptUtils::Load(void) {
fd = open(dev_path.c_str(), O_RDWR);
if (fd < 0) {
ALOGE("failed to open block dev %s, %d\n", dev_path.c_str(), errno);
return -1;
}
int ret = ioctl(fd, BLKSSZGET, &block_size);
if (ret < 0) {
ALOGE("failed to get block size %d\n", errno);
return -1;
}
// read primary header
lseek64(fd, block_size, SEEK_SET);
ret = read(fd, &gpt_primary, sizeof gpt_primary);
if (ret < 0) {
ALOGE("failed to read gpt primary header %d\n", errno);
return -1;
}
if (ValidateGptHeader(&gpt_primary)) {
ALOGE("error validating gpt header\n");
return -1;
}
// read partition entries
entry_array.resize(gpt_primary.entry_count);
uint32_t entries_size = gpt_primary.entry_size * gpt_primary.entry_count;
lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
ret = read(fd, entry_array.data(), entries_size);
if (ret < 0) {
ALOGE("failed to read gpt partition entries %d\n", errno);
return -1;
}
// read gpt back header
lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
ret = read(fd, &gpt_backup, sizeof gpt_backup);
if (ret < 0) {
ALOGE("failed to read gpt backup header %d\n", errno);
return -1;
}
if (ValidateGptHeader(&gpt_backup)) {
ALOGW("error validating gpt backup\n"); // just warn about it, not fail
}
// Create map <partition name, gpt_entry pointer>
auto get_name = [](const uint16_t *efi_name) {
char name[37] = {};
for (size_t i = 0; efi_name[i] && i < sizeof name - 1; ++i) name[i] = efi_name[i];
return std::string(name);
};
for (auto const &e : entry_array) {
if (e.name[0] == 0)
break; // stop at the first partition with no name
std::string s = get_name(e.name);
entries[s] = const_cast<gpt_entry *>(&e);
}
return 0;
}
gpt_entry *GptUtils::GetPartitionEntry(std::string name) {
return entries.find(name) != entries.end() ? entries[name] : nullptr;
}
int GptUtils::Sync(void) {
if (!fd)
return -1;
// calculate crc and check if we need to update gpt
gpt_primary.entries_crc32 = crc32(0, reinterpret_cast<uint8_t *>(entry_array.data()),
entry_array.size() * sizeof(gpt_entry));
// save old crc
uint32_t crc = gpt_primary.crc32;
gpt_primary.crc32 = 0;
gpt_primary.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_primary), sizeof gpt_primary);
if (crc == gpt_primary.crc32)
return 0; // nothing to do (no changes)
ALOGI("updating GPT\n");
lseek64(fd, block_size * gpt_primary.current_lba, SEEK_SET);
int ret = write(fd, &gpt_primary, sizeof gpt_primary);
if (ret < 0) {
ALOGE("failed to write gpt primary header %d\n", errno);
return -1;
}
lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
if (ret < 0) {
ALOGE("failed to write gpt partition entries %d\n", errno);
return -1;
}
// update GPT backup entries and backup
lseek64(fd, block_size * gpt_backup.start_lba, SEEK_SET);
ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
if (ret < 0) {
ALOGE("failed to write gpt backup partition entries %d\n", errno);
return -1;
}
gpt_backup.entries_crc32 = gpt_primary.entries_crc32;
gpt_backup.crc32 = 0;
gpt_backup.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_backup), sizeof gpt_backup);
lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
ret = write(fd, &gpt_backup, sizeof gpt_backup);
if (ret < 0) {
ALOGE("failed to write gpt backup header %d\n", errno);
return -1;
}
fsync(fd);
return 0;
}
GptUtils::~GptUtils() {
if (fd) {
Sync();
close(fd);
}
}
} // namespace aidl::android::hardware::boot
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